filesystems: add set_nlink()

Replace remaining direct i_nlink updates with a new set_nlink()
updater function.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Tested-by: Toshiyuki Okajima <toshi.okajima@jp.fujitsu.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 0defe0b..be6668b 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -3418,7 +3418,7 @@
 		inode->i_uid |= le16_to_cpu(raw_inode->i_uid_high) << 16;
 		inode->i_gid |= le16_to_cpu(raw_inode->i_gid_high) << 16;
 	}
-	inode->i_nlink = le16_to_cpu(raw_inode->i_links_count);
+	set_nlink(inode, le16_to_cpu(raw_inode->i_links_count));
 
 	ext4_clear_state_flags(ei);	/* Only relevant on 32-bit archs */
 	ei->i_dir_start_lookup = 0;